1. Field of the Invention
The present invention relates to an exhaust device suitable for an engine, especially a V-type engine, in a vehicle such as a motorcycle.
2. Description of the Related Art
From a viewpoint of an environmental problem and the like, a catalyst is loaded in an exhaust device in order to purify exhaust gas of an engine. It is generally known that in order to conform to emission standards (for example, European EUR04 and so on), it is necessary to dispose the catalyst close to an exhaust port to some extent.
Meanwhile, in an ordinary twin engine such as what is called a V-type engine, a method of connecting exhaust pipes of cylinders via a connecting pipe is effective for improvement of torque characteristics, and so on.
Patent Document 1 or Patent Document 2 discloses a concrete example of an exhaust device or the like in an engine of this type.
Patent Document 1: Japanese Examined Patent Application Publication No. 04-13196
Patent Document 2: Japanese Patent No. 4108381
In the conventional exhaust devices, a measure is taken such as disposing the connecting pipe connecting the exhaust pipes on a side of the vehicle (for example, a side of the engine), but this layout is not easy because of space and the like.
Further, in conventional engines including the V-type engine and the like, it has not been necessarily easy to achieve an improvement of the torque characteristics and so on while realizing the exhaust pipe layout necessary for clearing the emission standards. That is, an attempt to satisfy both involves problems such as that middle and low speed range torques are lost or what is called a torque valley occurs.